Add a setting to VMs that allows users to trigger cloud-init full reconfiguration. (#767)

This will trigger cloud-init reinitialization, including ssh keys update
and static network config refresh.

packages/apps/virtual-machine/README.md

@@ -53,6 +53,7 @@ virtctl ssh <user>@<vm>
 | `sshKeys`                 | List of SSH public keys for authentication. Can be a single key or a list of keys.                         | `[]`             |
 | `cloudInit`               | cloud-init user data config. See cloud-init documentation for more details.                                | `#cloud-config
 ` |
+| `cloudInitSeed`           | A seed string to generate an SMBIOS UUID for the VM.                                                       | `""`             |
 
 ## U Series
 

packages/apps/virtual-machine/templates/_helpers.tpl

@@ -49,3 +49,23 @@ Selector labels
 app.kubernetes.io/name: {{ include "virtual-machine.name" . }}
 app.kubernetes.io/instance: {{ .Release.Name }}
 {{- end }}
+
+{{/*
+Generate a stable UUID for cloud-init re-initialization upon upgrade.
+*/}}
+{{- define "virtual-machine.stableUuid" -}}
+{{- $source := printf "%s-%s-%s" .Release.Namespace (include "virtual-machine.fullname" .) .Values.cloudInitSeed }}
+{{- $hash := sha256sum $source }}
+{{- $uuid := printf "%s-%s-4%s-9%s-%s" (substr 0 8 $hash) (substr 8 12 $hash) (substr 13 16 $hash) (substr 17 20 $hash) (substr 20 32 $hash) }}
+{{- if eq .Values.cloudInitSeed "" }}
+  {{- /*  Try to save previous uuid to not trigger full cloud-init again if user decided to remove the seed. */}}
+  {{- $vmResource := lookup "kubevirt.io/v1" "VirtualMachine" .Release.Namespace (include "virtual-machine.fullname" .) -}}
+  {{- if $vmResource }}
+    {{- $existingUuid := $vmResource | dig "spec" "template" "spec" "domain" "firmware" "uuid" "" }}
+    {{- if $existingUuid }}
+      {{- $uuid = $existingUuid }}
+    {{- end }}
+  {{- end }}
+{{- end }}
+{{- $uuid }}
+{{- end }}

packages/apps/virtual-machine/templates/vm.yaml

@@ -68,6 +68,8 @@ spec:
           requests:
             memory: {{ .Values.resources.memory | quote }}
         {{- end }}
+        firmware:
+          uuid: {{ include "virtual-machine.stableUuid" . }}
         devices:
           {{- if .Values.gpus }}
           gpus:

packages/apps/virtual-machine/values.schema.json

@@ -199,6 +199,11 @@
       "type": "string",
       "description": "cloud-init user data config. See cloud-init documentation for more details.",
       "default": "#cloud-config\n"
+    },
+    "cloudInitSeed": {
+      "type": "string",
+      "description": "A seed string to generate an SMBIOS UUID for the VM.",
+      "default": ""
     }
   }
 }

packages/apps/virtual-machine/values.yaml

@@ -57,3 +57,12 @@ sshKeys: []
 ##
 cloudInit: |
   #cloud-config
+
+## @param cloudInitSeed A seed string to generate an SMBIOS UUID for the VM.
+cloudInitSeed: ""
+## Change it to any new value to force a full cloud-init reconfiguration. Change it when you want to apply
+## to an existing VM settings that are usually written only once, like new SSH keys or new network configuration.
+## An empty value does nothing (and the existing UUID is not reverted). Please note that changing this value
+## does not trigger a VM restart. You must perform the restart separately.
+## Example:
+## cloudInitSeed: "upd1"

packages/apps/vm-instance/README.md

@@ -51,6 +51,7 @@ virtctl ssh <user>@<vm>
 | `sshKeys`          | List of SSH public keys for authentication. Can be a single key or a list of keys.                         | `[]`             |
 | `cloudInit`        | cloud-init user data config. See cloud-init documentation for more details.                                | `#cloud-config
 ` |
+| `cloudInitSeed`    | A seed string to generate an SMBIOS UUID for the VM.                                                       | `""`             |
 
 ## U Series
 

packages/apps/vm-instance/templates/_helpers.tpl

@@ -49,3 +49,23 @@ Selector labels
 app.kubernetes.io/name: {{ include "virtual-machine.name" . }}
 app.kubernetes.io/instance: {{ .Release.Name }}
 {{- end }}
+
+{{/*
+Generate a stable UUID for cloud-init re-initialization upon upgrade.
+*/}}
+{{- define "virtual-machine.stableUuid" -}}
+{{- $source := printf "%s-%s-%s" .Release.Namespace (include "virtual-machine.fullname" .) .Values.cloudInitSeed }}
+{{- $hash := sha256sum $source }}
+{{- $uuid := printf "%s-%s-4%s-9%s-%s" (substr 0 8 $hash) (substr 8 12 $hash) (substr 13 16 $hash) (substr 17 20 $hash) (substr 20 32 $hash) }}
+{{- if eq .Values.cloudInitSeed "" }}
+  {{- /*  Try to save previous uuid to not trigger full cloud-init again if user decided to remove the seed. */}}
+  {{- $vmResource := lookup "kubevirt.io/v1" "VirtualMachine" .Release.Namespace (include "virtual-machine.fullname" .) -}}
+  {{- if $vmResource }}
+    {{- $existingUuid := $vmResource | dig "spec" "template" "spec" "domain" "firmware" "uuid" "" }}
+    {{- if $existingUuid }}
+      {{- $uuid = $existingUuid }}
+    {{- end }}
+  {{- end }}
+{{- end }}
+{{- $uuid }}
+{{- end }}

packages/apps/vm-instance/templates/vm.yaml

@@ -40,6 +40,8 @@ spec:
           requests:
             memory: {{ .Values.resources.memory | quote }}
         {{- end }}
+        firmware:
+          uuid: {{ include "virtual-machine.stableUuid" . }}
         devices:
           {{- if .Values.gpus }}
           gpus:

packages/apps/vm-instance/values.schema.json

@@ -180,6 +180,11 @@
       "type": "string",
       "description": "cloud-init user data config. See cloud-init documentation for more details.",
       "default": "#cloud-config\n"
+    },
+    "cloudInitSeed": {
+      "type": "string",
+      "description": "A seed string to generate an SMBIOS UUID for the VM.",
+      "default": ""
     }
   }
 }

packages/apps/vm-instance/values.yaml

@@ -55,3 +55,12 @@ sshKeys: []
 ##
 cloudInit: |
   #cloud-config
+
+## @param cloudInitSeed A seed string to generate an SMBIOS UUID for the VM.
+cloudInitSeed: ""
+## Change it to any new value to force a full cloud-init reconfiguration. Change it when you want to apply
+## to an existing VM settings that are usually written only once, like new SSH keys or new network configuration.
+## An empty value does nothing (and the existing UUID is not reverted). Please note that changing this value
+## does not trigger a VM restart. You must perform the restart separately.
+## Example:
+## cloudInitSeed: "upd1"